Improvement in lathe-chucks



YD.' H. TIERNEY.

LATER-CHUCK.

No. 177,03'1. I 'Patented May 2,1876.

- lockingitherscrews.andjawsi .Tf [OFFICE:

DENNSQH. TIERNEY, OF FORSTVIBLE CONNECTICUT. 'j

Specificationforming,part=of Letters Patent No. 177,031, dated May 2, 1876; application'led J anuary-21, 1876.v

To alt-.whom .z'tmayooncera:

Bent. .known Y.that I, DENNIS, H. TIERNEY, of-z'orestville,:in thercountyof Hartford and justin g device for-resettin g .the serewfindica-tor;

to compensate for -wear 5 also, of a device forv In the accompanying drawing, `lligureLis a face view of a lathe-cliutik,.whichtl embodies my invention; Fig. 2,.adetached-. elesration, showing the'outer end of one'screw and jaw. Fig. 3 is a like view, showing one 'ot' the screws and its locking mechanism, aiidFig. 4-

is 'a sectional view on line me of Fig. 1.A

I provide the chuck. with three or more jaws, A A A, each of which are forced out and in by an independent screw, B, substantiallythe same as in lathe-chucks now in common use. Upon .the face of the chuck vand contiguous to each jawB, I form a. series of graduation-marks, C, and upon each of the jaws A Iyprovide a pointer or index, a, which moves with the jaws and passes over said series of graduation-marks, thereby indicating lthe position of thejaws. The pointer a is so placedon the jaws A that when they are all on the same graduation-mark-as, for instance, on mark 4in-the inner ends ofthe jaws will all bethesame distance from the center of the chuck. Upon the outer end i' the screws B at the edge ofthe chuck, I form an indicator or index, b, surrounding which thereis a series of graduation-marks, D, and numbers, whereby each revolution of .the screw or fractional part thereofl is `correctly indicated. The indicator b is for a moredelicate adjustment than can be made by the indicator a, but in a measure both are used conjointly and should be so set as to correspond-l for instance, suppose the jaws are to. be set with the indicator a. on mark 4. Said indieator is first observed until near that point,l and then `the .indicator b is observed andset 'ltmarkZO,"` when, it' properly adjusted, themdicatorg-a will be exactly central with mark 4.

The reason thatthe indicator b gives -a finer or more delicate adjustment than indicator .a

is, that it moves over a fargreater surfacc,.ai.id

thereforea movement ofthe jaw A and indicator. a that would .be almost imperceptible wouldbe clearlyindicatedby several, degrees uponthe. serewfindicator.v b. In order to compensate for the wearof theparts, I. construct the inidcatorb so that it may be moved -onlthe screw andthereby correctly 'indicate Athe position 'ofthe jaws. Any construction that `will allowits positiouon =the screw to bechan ged when dcsiredywill answer the .purposesof this part` of,my.invention ..^I tbrmtheindicator b on a l c0l1ar, e, which.L is .driven ,.on. the screw. j nstthat the jaws may all be held or locked in a desired position beyond any liability to be accidentally moved. 1n such ease I form teeth in the edge of the screw-collar c, thereby forming the same into a spur-gear, c. into this gear c is a similar gear, d, revolving upon a screw-stud, e. the gears c d I form a series of graduationmarks, D, and in the edge ofthe chuck I place a pin, j', which answers i'or an indicator. rlhese marks D 'and indicator f perform precisely the same function, and in the salne manner, as the marks D and indicator b hereinbefore described, the. only difference being that the marks rotate and the indicator is stationary.

It will also be noticed that the result is the same, whether the marks D are on the gear' c( v or gear cl, or both, and the indicator f may beV Meshing Upon one or both of 2 'i y 'j 177,031

inward, forcing its shoulder `against thegcar d, and preventing it from rotating, whereby any endwise pressure upon the jaws will not be liable to move them in the least. A e

In ordinary lathe-chucks two Sets of jaws are formed fromasolid .piece of metal by the peculiar shape of the jaw; theends of which form the smaller r inner jaws, and a step on said jaws forms the outer jaws for griping lai-ger articles. The outer and inner jaws 'are' used entirely independent of each otherthat is, only .one set can be used at once-and when `the inner ones are-in use the outer ones project so'` t'ar as to oftentimes seriously interfere with the,convenientY use of the chuck. To

avoid lthis'l inconveneiice I make the outerjaws detachable Various means can be employed for this purpose; Abut perhaps the best mode of applying tlieprinciple of this part of Vmy invention is as follows, viz: In the outer end'otl the jaw I ,form a transverse groove, li., inthe bottom of which I borcja hole, .in which hole I fit the shank kof the outer jaw E." At the junction of the shank k and jaw E there is a transverse bar, m, which fits in the groove h, thereby preventing the jawfroin twisting. 'A small pin, a, is then put through the shank k and body of ther main4 jaw A, which prevents the outer jaws E from slipping out of place.

When thus 'secured the outer jaws are used the same as tlieouter jaws of ordinary lathe chucks.; but'when the in ner jaws are to be used the pin a and therout'er jaws E are removed so that no part of the chuck projects outward beyond the'i'ace 'f the inner jaws, whereby the tool-rest and other tools can be brought- A, ation marks and figures have been placed upon i the face of the chuck, and amark upon one sidegofthejaw; but so far as I know a pointer, whichprojects laterally to one side of' the jaws, as shown, has never been used in lathe-chucks, the advantage ot' the latter over the former being that bo'th the pointer and graduationinarks can be readily observed when looking -directly npoii the face, whereas in thefornier both could not beobserved, exceptwhen looked at in an oblique direction, and then only when viewed upon a particular side of the jaw.

I claim as my invention- 4 y 1'. In 'a lathe-chuck two or more independent holding-jaws,two' or more' independent screws, each provided with an indicator, b, all operating together substantially as described,

and for the purpose set forth. e I i 2. In a'lathe-chuck the indicator a,mo'ving over graduation-in ai'ks on the face ofthe chuck, in combination with the jaw A, screw B, and indicator. b, substantially' as described. 3. In a lathe-chuck the combination of the indicator b, adjustable collar c, and screw B, substantially as described.` i j 4. The lockingmechanism c d c in combination with the screw B and jaw A, substantially asydescribed. l j

i x I 'J y DENNIS H. TIERNEY. Witnesses:

J AMES Summen, WM. U. RICHARDS. 

